451 research outputs found
Characterisation of HTSC ceramics from their resistive transition
The resistivity vs. temperature relation in bulk ceramic HTSC under
self-field conditions as well as in weak external magnetic fields is modelled
by local Lorentz force induced fluxon motion with temperature dependent
pinning. A pinning force density and two viscous drag coefficients in
intergrain and intragrain regions, respectively, can be used as characteristic
parameters describing the temperature, current, and external field dependences
of the sample resistance.Comment: 12 pages, LaTeX2e, 6 figures (epsfig), to be published in Supercond.
Sci. and Techno
Cluster tails for critical power-law inhomogeneous random graphs
Recently, the scaling limit of cluster sizes for critical inhomogeneous
random graphs of rank-1 type having finite variance but infinite third moment
degrees was obtained (see previous work by Bhamidi, van der Hofstad and van
Leeuwaarden). It was proved that when the degrees obey a power law with
exponent in the interval (3,4), the sequence of clusters ordered in decreasing
size and scaled appropriately converges as n goes to infinity to a sequence of
decreasing non-degenerate random variables.
Here, we study the tails of the limit of the rescaled largest cluster, i.e.,
the probability that the scaling limit of the largest cluster takes a large
value u, as a function of u. This extends a related result of Pittel for the
Erd\H{o}s-R\'enyi random graph to the setting of rank-1 inhomogeneous random
graphs with infinite third moment degrees. We make use of delicate large
deviations and weak convergence arguments.Comment: corrected and updated first referenc
Comparison of the Meat Quality of Turopolje, German Landrace x Turopolje and German Landrace x Pietrain Pigs
Aim of the study was to evaluate, if the mixed breed German Landrace x Turopolje (L x T) was suitable for conventional fattening and the production of high quality palatable meat. Hence, we chose to study the carcass characteristics of three different breeds: true bred Turopolje (T x T) (n=15), an autochthonous Croatian breed, German Landrace x Pietrain (L x P) (n=19), a typical German pig hybrid and German Landrace x Turopolje (L x T) (n=23) as mixed breed. All three breeds were kept in a conventional fattening indoor system. The data consisted of the chemical and physical values of the carcass and the difference between breeds during breeding and fattening. All pigs were fattened with a conventional ad libidum feeding system. The feed consisted of an optimal mixture for the fattening of L x P. The daily feed intake and the weight from birth until the end of the fattening was recorded every 14 days. The quality of the carcass was evaluated at the age of 20 and 25 weeks. The measurement of the carcass was based on the âRichtlinie fĂŒr die StationsprĂŒfung auf Mastleistung, Schlachtkörperwert und Fleischbeschaffenheit beim Schweinâ published by the national German control office. L x T showed the lowest feed intake per kg carcass compared to the other breeds. The quality of meat was characterized by pH, conductance, intramuscular fat and water holding capacity. L x T showed a trend for a lower conductance in week 25. The value of pH and water holding capacity was not significant between the breeds. Surprisingly, the intramuscular fat of L x T was by trend higher compared to L x P and significantly lower than T x T (p < 0.05). L x T had by trend a higher carcass weight and a larger carcass length compared to L x P, which was significantly higher than T x T (p < 0.05). In conclusion, the new breed L x T seems to be suitable for an indoor fattening system and produces a high quality palatable meat. The energy and protein intake should be slightly reduced, which would reduce the cost of meat production
Would Functional Agricultural Foods Improve Human Health?
Concern over diet-health relationships has moved to the forefront of public health concerns in the UK and much of the developed world. It has been estimated, for example, that obesity costs the UK National Health Service up to ÂŁ6b per year (Rayner and Scarborough, 2005), but if all consumers were to follow recommended healthy eating guidelines there would be major implications for food consumption, land use and international trade (Srinivasan et al, 2006). This is unlikely to happen, at least in the short term, but it is realistic to anticipate some dietary adjustment toward the recommendations, resulting in an improvement in diet quality (Mazzocchi et al, 2007). Although consumers are reluctant to make major changes to their diets, they may be prepared to substitute existing foods for healthier alternatives. Three of the most prominent nutritional recommendations are to consume more fruit and vegetables, which contain phytochemicals beneficial to health, reduce consumption of saturated fatty acids (SFA) and increase intake of long-chain n-3 fatty acids (FA). In the first case, consumption of fruit and vegetables has been stable at around three 80 g portions per person per day according to the Health Survey for England. It is estimated that 42,200 deaths per year could be avoided in England and 411,000 Quality Adjusted Life Years (QALYs) could be saved if fruit and vegetable consumption were increased to the recommended 5 portions per day (Ofcom 2006). As well as continuing to encourage people to eat more, it could be desirable to âintensifyâ the beneficial phytochemical content of existing fruit and vegetables.Agribusiness, Agricultural and Food Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Industrial Organization,
Study of flare energy release using events with numerous type III-like bursts in microwaves
The analysis of narrowband drifting of type III-like structures in radio
bursts dynamic spectra allows to obtain unique information about primary energy
release mechanisms in solar flares. The SSRT spatially resolved images and a
high spectral and temporal resolution allow direct determination not only the
positions of its sources but also the exciter velocities along the flare loop.
Practically, such measurements are possible during some special time intervals
when the SSRT (about 5.7 GHz) is observing the flare region in two high-order
fringes; thus, two 1D scans are recorded simultaneously at two frequency bands.
The analysis of type III-like bursts recorded during the flare 14 Apr 2002 is
presented. Using-muliwavelength radio observations recorded by SSRT, SBRS,
NoRP, RSTN we study an event with series of several tens of drifting microwave
pulses with drift rates in the range from -7 to 13 GHz/s. The sources of the
fast-drifting bursts were located near the top of the flare loop in a volume of
a few Mm in size. The slow drift of the exciters along the flare loop suggests
a high pitch-anisotropy of the emitting electrons.Comment: 16 pages, 6 figures, Solar Physics, in press, 201
Switching kinetics of ferroelectric polymer nanomesas
The switching dynamics and switching time of ferroelectric nanomesas grown from the paraelectric phase of ultrathin LangmuirâBlodgett vinylidene fluoride and trifluoroethylene copolymer films are investigated. Ferroelectric nanomesas are created through heat treatment and self-organization and have an average height of 10 nm and an average diameter of 100 nm. Ferroelectric nanomesas are highly crystalline and are in the ferroelectric phase and switch faster than 50 ÎŒs. The dependence of switching time on applied voltage implies an extrinsic switching nature
A Parametric Study of Erupting Flux Rope Rotation. Modeling the "Cartwheel CME" on 9 April 2008
The rotation of erupting filaments in the solar corona is addressed through a
parametric simulation study of unstable, rotating flux ropes in bipolar
force-free initial equilibrium. The Lorentz force due to the external shear
field component and the relaxation of tension in the twisted field are the
major contributors to the rotation in this model, while reconnection with the
ambient field is of minor importance. Both major mechanisms writhe the flux
rope axis, converting part of the initial twist helicity, and produce rotation
profiles which, to a large part, are very similar in a range of shear-twist
combinations. A difference lies in the tendency of twist-driven rotation to
saturate at lower heights than shear-driven rotation. For parameters
characteristic of the source regions of erupting filaments and coronal mass
ejections, the shear field is found to be the dominant origin of rotations in
the corona and to be required if the rotation reaches angles of order 90
degrees and higher; it dominates even if the twist exceeds the threshold of the
helical kink instability. The contributions by shear and twist to the total
rotation can be disentangled in the analysis of observations if the rotation
and rise profiles are simultaneously compared with model calculations. The
resulting twist estimate allows one to judge whether the helical kink
instability occurred. This is demonstrated for the erupting prominence in the
"Cartwheel CME" on 9 April 2008, which has shown a rotation of \approx 115
degrees up to a height of 1.5 R_sun above the photosphere. Out of a range of
initial equilibria which include strongly kink-unstable (twist Phi=5pi), weakly
kink-unstable (Phi=3.5pi), and kink-stable (Phi=2.5pi) configurations, only the
evolution of the weakly kink-unstable flux rope matches the observations in
their entirety.Comment: Solar Physics, submitte
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